<?php
//给定课程模块ID，获取指定资源

/*---------------------一、PHP文件引用----------------------------------*/
require('../config.php');
require_once($CFG->dirroot.'/mod/resource/lib.php');
require_once($CFG->dirroot.'/mod/resource/locallib.php');
require_once($CFG->libdir.'/completionlib.php');

/*---------------------二、变量参数定义-------------------------------*/
$id=$_GET['id'];//课程模块ID,即mdl_course_moudle表中的'id'
//$id=19;//测试
//$id=optional_param('id', 0, PARAM_INT); // Course Module ID
$r= optional_param('r', 0, PARAM_INT);// Resource instance ID
$redirect = optional_param('redirect', 0, PARAM_BOOL);

/*------------------------三、获取资源描述-----------------------*/
if ($r) {
    if (!$resource = $DB->get_record('resource', array('id'=>$r))) {
        resource_redirect_if_migrated($r, 0);
        print_error('invalidaccessparameter');
    }
    $cm = get_coursemodule_from_instance('resource', $resource->id, $resource->course, false, MUST_EXIST);

} else {
    if (!$cm = get_coursemodule_from_id('resource', $id)) {
        resource_redirect_if_migrated(0, $id);
        print_error('invalidcoursemodule');
    }
    $resource = $DB->get_record('resource', array('id'=>$cm->instance), '*', MUST_EXIST);
}

/*----------------------四、获取课程描述----------------------*/
$course = $DB->get_record('course', array('id'=>$cm->course), '*', MUST_EXIST);

/*---------------五、确保登录用户才能获取资源----------------*/
require_course_login($course, true, $cm);
$context = context_module::instance($cm->id);
require_capability('mod/resource:view', $context);

/*------------------------六、触发事件----------------------------*/
resource_view($resource, $course, $cm, $context);

/*------------------------七、重定向网页---------------------------*/
$PAGE->set_url('/mod/resource/view.php', array('id' => $cm->id));
if ($resource->tobemigrated) {
    resource_print_tobemigrated($resource, $cm, $course);
    die;
}

/*------------------------八、获取资源存储位置---------------------------*/
$fs = get_file_storage();
$files = $fs->get_area_files($context->id, 'mod_resource', 'content', 0, 'sortorder DESC, id ASC', false); 
if (count($files) < 1) {
    resource_print_filenotfound($resource, $cm, $course);
    die;
} else {
    $file = reset($files);
    unset($files);
}

/*-------------------九、根据用户选择进行文件下载/保存---------------------*/
$resource->mainfile = $file->get_filename();
$displaytype = resource_get_final_display_type($resource);
if ($displaytype == RESOURCELIB_DISPLAY_OPEN || $displaytype == RESOURCELIB_DISPLAY_DOWNLOAD) {
    if (strpos(get_local_referer(false), 'modedit.php') === false) {
        $redirect = true;
    }
}
if ($redirect && !course_get_format($course)->has_view_page() &&
        (has_capability('moodle/course:manageactivities', $context) ||
        has_capability('moodle/course:update', context_course::instance($course->id)))) {
    $redirect = false;
}
if ($redirect) {
    $path = '/'.$context->id.'/mod_resource/content/'.$resource->revision.$file->get_filepath().$file->get_filename();
    $fullurl = moodle_url::make_file_url('/pluginfile.php', $path, $displaytype == RESOURCELIB_DISPLAY_DOWNLOAD);
    redirect($fullurl);
}

/*------------------------十、下载/保存----------------------------*/
switch ($displaytype) {
    case RESOURCELIB_DISPLAY_EMBED:
        resource_display_embed($resource, $cm, $course, $file);
        break;
    case RESOURCELIB_DISPLAY_FRAME:
        resource_display_frame($resource, $cm, $course, $file);
        break;
    default:
        resource_print_workaround($resource, $cm, $course, $file);
        break;
}

?>